Prostacyclin synthetase activity in diabetic human venous tissue.

The purpose of this study was to ascertain if alterations were present in the prostacyclin synthetase (PGI2ase) activity in diabetic human venous tissue. Saphenous veins were obtained from a group of 12 patients with (HSV-D) or without (HSV-ND) diabetes who were undergoing coronary artery bypass surgery. 14C-Labeled prostaglandin endoperoxide (PGH2) was incubated for 2 minutes with venous microsomal protein. The products were separated by thin-layer chromatography and quantified by radiochromatographic scan. PGI2ase activity was determined by the formation of 6-keto-PGF1 alpha, the stable breakdown product of prostacyclin (PGI2). Results of this study indicate the following: both HSV-ND and HSV-D specimens have active PGI2ase and are capable of forming PGI2; there is no difference between PGI2ase activity in HSV-D and HSV-ND specimens; and in diabetes mellitus, any defects in PGI2 production similar to those associated with diabetes in other investigations must reside higher in the arachidonic acid cascade.

Fasciotomy in vascular trauma: is it too much, too often?

Fasciotomy has been used as a prophylactic measure against development of compartment syndrome and as a treatment modality when the syndrome has developed in patients suffering vascular trauma. The hospital records of 36 patients who underwent surgical repair of their traumatic vascular injuries were reviewed. All 36 patients had at least one indication for fasciotomy at the time of repair; i.e., ischemic time of more than 6 hours or combined arterial and venous injury. Prophylactic fasciotomies were performed in 18 of the patients at the time of vascular repair; 18 did not have fasciotomies performed at the time of initial repair. The decision to perform a fasciotomy was made by the operating surgeon based on well-defined criteria. Hospital stay was significantly longer for the fasciotomy group. Four of the fasciotomy-related complications were infective in nature. Only one patient who did not undergo fasciotomy at the time of original repair developed a compartment syndrome during the postoperative period. Selective fasciotomy based on well-defined criteria instead of serial physical examinations or measurement of compartment pressures will effectively save limbs; there is an increased hospital stay.

Management strategy of vascular injuries associated with pelvic fractures.

To establish the frequency of major vascular trauma, facilitate recognition of potential injury based on fracture pattern, and formulate a systematic approach to evaluation and management, we studied 429 consecutive patients with acute blunt pelvic fracture. Fracture patterns were grouped as non-ring brakes (n = 43), anterior pelvic ring (n = 197), posterior pelvic ring (n = 104), or acetabular (n = 85) involvement. Mean age was 31 (range 2 to 90); 55% were male. Injuries resulted primarily from motor vehicle accidents (31%), pedestrian injuries (26%), and motorcycle accidents (19%). The fracture pattern was correlated with the occurrence of documented vascular injury, modality of management, transfusion greater than or equal to 10 units in the first day, associated injuries, and outcome. Laparotomy was performed in 22 patients (5%), but helpful only if associated visceral injuries were encountered. There were no instances of iliac or femoral vascular injuries. Hemodynamically unstable patients (BP less than 90) with major pelvic fractures and no other documented source of bleeding underwent pelvic angiography. Posterior ring disruption was associated with vascular injury requiring intervention (p less than 0.001). The occurrence of associated injuries (p less than 0.001), need of greater than 10 units of blood transfusion in the first 24 hours (p less than 0.005), and death (p less than 0.01) were consequences of posterior ring disruption. Based on this experience we conclude that: (1) aortoiliac and femoral arterial as well as iliofemoral venous injuries are a very rare consequence of pelvic fracture; (2) pelvic fracture with posterior ring disruption has a higher incidence of vascular injury necessitating intervention, associated injury, major transfusion requirement, and death; (3) early interventional radiology is efficacious in the control of arterial disruption caused by pelvic fracture; and (4) a tailored management strategy using the expertise of the vascular and orthopedic surgeon as well as the radiologist is required for recalcitrant hemorrhage.

Infrainguinal revascularization for limb salvage in patients with end-stage renal disease.

We studied the efficacy of infrainguinal bypass for limb salvage in patients with end-stage renal disease. The patency of 42 femoropopliteal and femorodistal bypasses, performed for limb salvage in 37 patients with end-stage renal disease, was assessed with Doppler ultrasonography and dye tests. Patency rates and limb salvage were determined by life-table analysis. Average age was 45 years (range, 28 to 61 years); 23 of the 37 were men. Twenty-three patients had diabetes mellitus, and 16 were smokers. Bypass procedures were done in 32 instances while the patients were maintained with chronic hemodialysis and in five instances with peritoneal dialysis; in five instances the patients had had successful renal transplantation. Indications for revascularization included pain at rest, nonhealing ulcer, or distal gangrene. Femoropopliteal bypass was done in 32 limbs; 10 were more distal procedures. Reversed saphenous vein was the conduit in 30 cases; prosthetic material was used in the remainder. Autogenous material was used in all distal bypasses. Four patients required graft revision during the initial hospitalization, but none thereafter. Two patients died within the operative period, nine within 18 months of operation. Nine major operations were required. Three-month cumulative graft patency was achieved in 41 cases and corresponding limb salvage in 33 cases; 18-month patency was achieved in 34 cases and overall limb salvage in 33 cases. Success of limb salvage most closely correlated with preoperative ankle-brachial ratio and level of bypass required.

Intraoperative intra-arterial urokinase infusion as an adjunct to Fogarty catheter embolectomy in acute arterial occlusion.

Sixteen patients, seven men and nine women (mean age of 66 years), with acute arterial ischemia were treated with operative thromboembolectomy by Fogarty catheterization and urokinase. Seven patients were diabetic, ten were hypertensive and six had prior vascular surgical treatment. The operative arteriograms confirmed vascular occlusive phenomenon. The ankle to brachial ratio was a mean of 0.02. Perioperatively, patients had anticoagulation with heparin systemically. All patients underwent transfemoral embolectomy using a Fogarty catheter. An initial retrieval of clots was accomplished, with documentation by arteriography, instillation of urokinase (50,000 units) and clamping of vessel for 15 minutes. Subsequent passage of the Fogarty catheter and repeat urokinase infusion resulted in further retrieval of clots and improvement by repeat intraoperative arteriography. All interventions resulted in clinical restoration of perfusion to the affected limb. Six patients had amputations of the lower extremities (one transmetatarsal and one below the knee) during the 30 day postoperative period. Improvement in distal run-off was demonstrated by intraoperative arteriography and increases in the ankle to brachial ratio from 0.1 to 1.04, with a mean of 0.54, were noted. No complications from bleeding occurred. One patient died postoperatively because of myocardial infarction. Salvage of the limb may increase with combined embolectomy and thrombolytic therapy.

Primary aortoenteric fistula: computed tomographic diagnosis of an atypical presentation.

A primary aortoenteric fistula is a potentially devastating complication of untreated aortic aneurysmal disease. The clinical presentation can be confusing, leading to a delay in diagnosis. Computed tomography (CT) can greatly assist in establishing the diagnosis. An unusual case of a primary aortoenteric fistula with an atypical presentation is described. The patient presented with symptoms indicating an exacerbation of recurrent nephrolithiasis. No clinical history of an abdominal aortic aneurysm or previous history of gastrointestinal hemorrhage was reported. A CT scan demonstrated extravasation of arterial contrast into the duodenum. The aorta was repaired with an in-line prosthetic graft. A review of the literature regarding this rare entity and surgical options are presented.

Analysis of inferior venacavography before Greenfield filter placement.

The value of routine preoperative inferior venacavography through a femoral approach was assessed in 64 patients who required a Greenfield inferior vena cava filter. Nearly 11% of the patients had an abnormality, for example, duplication of the inferior vena cava, circumaortic renal vein, interrupted or discontinuous inferior vena cava, and so on, requiring an alternate approach to placement. No deaths or complications occurred upon recognition of the anatomic variant before filter placement. In three of the seven abnormalities encountered, adequate visualization and filter placement could only have been accomplished through femoral catheterization. Preoperative cavograms before Greenfield filter placement should be routinely performed using a femoral approach in the absence of contraindications to this technique.

Analysis of cardiovascular and pulmonary responses to endothelin-1 and endothelin-3 in the anesthetized cat.

Cardiovascular and pulmonary responses to endothelin (ET)-1, ET-3 and neuropeptide Y (NPY) were investigated in the anesthetized cat. ET-1, 0.1 to 1 nmol/kg i.v., decreased or elicited biphasic changes in arterial pressure (AP), whereas ET-3, in the same doses, decreased AP. Both ETs increased cardiac output (CO) and, at the highest doses, a secondary decrease in CO was observed. NPY, 0.3 to 3 nmol/kg i.v., increased AP and at the highest dose decreased CO. All three peptides had inconsistent effects on right ventricular contractile force and increased central venous pressure. ET-1 at lower doses increased heart rate (HR) and, at 1 nmol/kg, caused a biphasic change. ET-3 increased HR, whereas NPY decreased HR. Systemic vascular resistance (SVR) was increased by NPY and decreased by ET-3, whereas ET-1 elicited biphasic changes. ET-1 and ET-3 increased pulmonary arterial pressure, left atrial pressure and caused biphasic changes in pulmonary vascular resistance (PVR). NPY had no significant effect on PAP or PVR. When pulmonary blood flow was maintained constant, ET-1 and ET-3 had only pulmonary vasoconstrictor activity, whereas NPY and the ET analog had no significant effect. The increase in SVR in response to NPY, the decrease in response to ET-3 or the biphasic change in response to ET-1 were not modified by meclofenamate, hexamethonium or propranolol. Increases in HR in response to ET-1 and ET-3 were reduced by the beta receptor and ganglionic blocking agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative effects of endothelin (ET-1) and U46619 on human saphenous vein and gastroepiploic artery, sources of human autologous grafts.

The effects of endothelin (ET-1) on smooth muscle contractile activity were investigated and compared in human saphenous vein and gastroepiploic artery, vessels frequently used in revascularization procedures. ET-1 contracted saphenous vein and gastroepiploic artery in a concentration-dependent manner. The peptide produced a greater maximal effect in the vein than in the artery and, in both preparations, ET-1 was less efficacious than U46619, an agent which mimics the actions of thromboxane A2 at the thromboxane A2/prostaglandin H2 receptor. The contractile response to ET-1 declined spontaneously at a more rapid rate in the artery than in the vein. The present data indicate that ET-1 has significant contractile activity in both vessels which are used for coronary arterial bypass surgery and suggest that although, a weaker vasoconstrictor than U46619, the peptide could induce vasospasm in both graft vessels.

Differential recovery of prostacyclin and endothelium-derived relaxing factor after vascular injury.

Differential recovery of prostacyclin and endothelium-derived relaxing factor after vascular injury. Am. J. Physiol. 262 (Heart Circ. Physiol. 31): H1449-H1457, 1992. The recovery of prostacyclin (prostaglandin I2, PGI2) synthesis and endothelium-derived relaxing factor (EDRF) activity, as demonstrated by acetylcholine (ACh)-induced relaxation, by rabbit aorta was examined up to 8 wk after balloon catheter-induced injury. Following injury, basal 6-keto-PGF1 alpha formation was decreased acutely; however, after 3 wk it was not different from control. Arachidonic acid-stimulated 6-keto-PGF1 alpha formation was decreased, returning to control levels at 3 and 8 wk for thoracic and abdominal aorta, respectively. ACh-induced relaxation did not return to control levels over the 8-wk study. Initiation of reendothelialization with a layer of hyperplastic endothelial cells overlying subendothelial fibrosis and intimal hyperplasia were present at 2-3 wk. Intimal hyperplasia appeared 2 wk after injury and progressed throughout the period of the study. These data indicate that following balloon catheter-induced injury the formation of both PGI2 and EDRF is reduced and that recovery follows a differential time course. In addition, the recovery of PGI2 formation did not coincide with the attenuation of intimal hyperplasia, whereas the relationship between EDRF formation and intimal hyperplasia is uncertain.